The present disclosure herein relates to an amine derivative, a material for an organic electroluminescent device and an organic electroluminescent device including the same, and more particularly, to a material for an organic electroluminescent device having high emission efficiency in a blue emission region and an organic electroluminescent device including the same.
In recent years, organic electroluminescent (EL) displays as one kind of image displays have been actively developed. Unlike liquid crystal displays and the like, organic EL displays are so-called self-luminescent displays which display images by emitting light from a luminescent material including an organic compound in the emission layer through recombination of holes and electrons injected from an anode and a cathode in the emission layer.
An example of an organic EL device known in the art is an organic EL device which includes an anode, a hole transport layer disposed on the anode, an emission layer disposed on the hole transport layer, an electron transport layer disposed on the emission layer, and a cathode disposed on the electron transport layer. Holes injected from the anode are injected via the hole transport layer into the emission layer. Meanwhile, electrons are injected from the cathode, and the injected electrons are injected via the electron transport layer into the emission layer. The holes and the electrons injected into the emission layer recombine to generate excitons within the emission layer. The organic EL device emits light generated by deactivation radiation of the excitons. The organic EL devices are not limited to the above-described configuration but may be changed to various suitable forms.
When organic EL devices are applied in display apparatuses, the low driving voltage, high emission efficiency and long life (i.e., lifetime or lifespan) of the organic EL device are required. To realize the low driving voltage, high emission efficiency and long life of the organic EL device, stabilization and normalization of the hole transport layer are contemplated. Aromatic amine-based compounds have been known as a hole transport material utilized in the hole transport layer, however, due to the low carrier resistance, there is a limitation in the life of the organic EL device. As a useful material for expanding the life of the organic EL device, for example, an amine derivative substituted with a heteroaryl ring has been suggested.
However, the suggested hole transport material is not considered to have sufficient emission efficiency. Particularly, since the emission efficiency of an organic EL device in a blue emission region is lower than in a red emission region and a green emission region, an increase in the emission efficiency in the blue emission region is required. In addition, since high temperature resistance of the organic EL device provided with the suggested hole transport material is not sufficient, a development of a novel material is required.